jesse jackson is calling on president obama to come to chicago to confront the gun crisis. today, jackson led mar cherz to the park where a 15-year-old girl was shot to death this week a mile from mr. obama's chicago home. the police say that it is likely she was the victim of a gang war. dean reynolds has discovered why gang gang related murders have become so difficult to solve. for almost seven years, pam and tom bosley have been hoping for a measure of justice. >> my son terrell was murdered april 4th, 2006. >> reporter: but no one has paid a price except terrell's family. >> the first year when this happened to terrell, it was real hard for me, and i tried to take my life twice. >> reporter: a suspect was arrested and tried, but then acquitted, the evidence was sparse, the witnesses willing to testify, few, even though terrell was shot in a church parking lot on a busy street. >> people were out there, but nobody said anything, yes, people coming home from work they were driving back you had to see somebody running down the street with a gun and shooting it. >> reporte